Testing system.



L. A. MORTIMER.

TESTING SYSTEM.

APPLICATION FILED MAR. 8. |918.

Patented 001;. 15, 1918.

mmm.,

ered in connection with LOUIS A. MORTIIVIER, OF NEW YORK7 N. Y.,ASSIGNOR TOWESTERN ELECTRIC COMPANY,

INCORPORATED, 0F NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TESTING SYSTEM.

Specification of Letters Patent.

Patented Oct. 15, 1918.

To all whom it may concern:

Be it known that I, LOUIS A. MORTIMER, a citizen of the United States,residing at New York, in the county of New York and State of New York,have invented certain new and useful Improvements in Testing Systems, ofwhich the following is a full, clear, concise, and exact description.

This invention relates to testing systems and more particularly to suchsystems employed in testing apparatus of telephone systems. l

An object of this invention is to provide a simple, accurate, reliableand inexpensive testing system for testing apparatus associated withtoll cord circuits employed for interconnecting toll lines or toll linesand trunk circuits with which may be joined the local line.

More specifically stated, this invention contemplates the provision ofapparatus and controlling devices and circuit organizations embodyingsuch apparatus and controlling devices by means of which alternatingcurrent and direct current supervisory relays of ,toll cord circuits maybe quickly tested under conditions simulating those met in actualservice.

This invention will be more fully understood from the followingdescription considthe accompanying drawing illustrating one embodimentthereof.

Referring to the drawing a toll cord circuit A is shown above the dottedline 2, 2 and to the left of the dotted line 3, 3, a testing circuit Bis shown to the right of the dotted line 3, 3, and a circuit controllingdevice C is shown below the dotted line 2, 2 and to the left of thedotted line 3, 3.

The toll cord circuit A terminates in two plugs 4 and 5 by means ofwhich connection may be made with the jacks of two toll lines (notshown) or with one toll line and with a toll switching trunk circuit(not shown) through which connection may be made with a local telephoneline (not shown). An alternating current supervisory relay 6 associatedwith the toll cord circuit A is controlled by alternating current over aconnected toll line to control a supervisory signal. The toll cordcircuit A is also provided with a direct current supervisory relay 7which may be controlled by direct current over a connected tollswitching trunk circuit to control a supervisory signal.

The testing circuit B is provided with Va plurality of multiple jacks 10and 11 with either of which the plug 4 0r the plug 5 may coperate toconnect the cord circuit A with the testing circuit, thereby toassociate the alternating current relay 6 and the direct current relay 7with the testing circuit. In order that the direct current relay 7 maybe tested under conditions simulating those met in actual practice, thetesting circuit is provided with two interrupters 12 and 13 which, whenconnected in circuit with the direct current supervisory relay 7 and asource of direct current cause the intermittent energiZation-of therelay. The interrupter 12 is provided with a relatively large number ofsegments so that the circuit of the relay 7 may be interrupted rapidly.vA high resistance 14 is in circuit with the interrupter 12. A source ofdirect current, interrupter 12 and the resistance 14 may be consideredas a source of intermittent current which simulates a long tollswitching trunk which is opened and closed rapidly. The interrupter 13is provided with a relatively small number offsegments in circuit withwhich is a low resistance 15. A source of direct current, interrupterV13 and the low resistance 15 may be considered as a source ofintermittent current which simulates a short toll switching trunk whichis slowly opened and closed.

In order that the alternating current relay 6 may be tested underconditions'simulating those met in actual practice, the testing circuitB is provided with a source of alternatin current 16 and an articialline. The artificial line comprises series resistances 17 18, 19 and 2Oand a bridged resistance 21. Another resistance 22 is normallyshort-circuited but when the short circuit is removed this resistance 22is included in series with the resistance 21. These two resistances 21and 22 then serve as a single bridged resistance. The inclusion of thisresistance 22 in the bridge serves to'alter the electricalcharacteristics of the artificial line. In fact, when resistance 21comprises the bridged resistance, this resistance and the seriesresistances may be considered as one artificial line and when theresistance 22 is included in the bridge with the resistance 21, thesetwo resistances and the series resistances vvmay be considered as asecond artificial line. When resistance 22 is short-circuitedand theartificial line and source of ringing Acurrent 16 are connected with thealternating current relay 6, the relay 6 receives minimum ringingcurrent, but when the short circuit is reconnected with a jack 9associated with the testing circuit B, the lcircuit controlling device Cmay be associated therewith. The

keys of the circuit controlling device C cont'rol the circuits of aplurality of relays in vthe testing circuit B which, in turn, controlthe connection of the sourcesof intermittent current, the artificiallines and-the source of alternating current with the `direct currentland alternating current supervisory relays. Y v

Having in mind this brief description of the apparatus employed in thetesting systeni, it is thought that the invention will be more fullyunderstood from a" description of Vthe operation thereof.k

Testing of direct current relay. Desiring to test the supervisory relaysof ,thertoll cord circuit A, the plug 4 thereof may be inserted in theack 10, and the plug 37 is inserted in the jack 9. 1f it is desiredfirst to testv the direct current supervisory relay 7, the key 30 isdepressed into its locking position, whereupon relays 40 and 41 of the.cord circuit A and relay 42 of the testing circuit B are operated over acircuit from battery through the left-hand winding of relay 40, thewindings of-,marginal relay 43 and relay 41, sleeve contacts of the plug4, the jacks 10 and 9, and the plug 37, resistance 44, contact 45 of key32, contact '46 of key 30, tip contacts of the plug 37 and the jack 9,and the windings of relay 42 and marginal relay 47 to ground. As alreadystated relays 43 and 47 are marginal and do not operate when resistance44'is included in circuit therewith. The operation of relay 40 causesthe operation of quick operating and slow releasing relay 24 to open thecircuit of a la1np25 and a slow operating relay 26 before the relayV 26can operate. The operation of relay 42 causes the intermittent operationof the supervisory relay 7 over a circuit from batterythrough'resistance 43, middle normal contact of relay 47, lower contactof relay 42, ring contacts of-the jack 10 and the plug 4, retardationcoil 49, winding of supervisory relay 7, normal contact of marginalrelay 43, retardation Ycoil 50, contact of relay'41, tip contacts of theplug 4 and the jack 10, upper contact of relay 42, upper normal contactof lrelay 47, normal contact of relay 51, resistance 14 and interrupter12 to ground. 1f the relay is-properly adjusted it will operateintermittently and cause the intermittent lighting of supervisory lamp52. If the lamp does not light Vor if it lights and remains lighted thetesting operator then knows that the relay 7 is notproperly adjusted tooper- Aate lon this low current when its circuit-is interrupted sorapidly. The testing operator will therefore adjust the relay until itfunctions properly. -The relay having been vtested under conditions ofmaximum length circuit, the testing operator then proceeds to test itunder conditions of minimum length of line with slowopening and closingof its circuit-which is done by the depresof line with rapid opening andclosing of its sion of the key 31. Upon the depressionof the key 31,theikey 30 is restored to normal position and rela-ys 40, 41, 42 and 51are operated'. The first three of these relays are operated over thesame circuit as hereinbef fore traced, withthis exceptiointhat contact5.3 of the key 31 instead of contact 46 of the -k'ey 30 is in thecircuit. Relay 51 operates over a circuit from battery through Vtheleft- Vhand winding of relay 40, windings of relays 43 and 41, sleevecontacts of the plug 4,

the jacks 10 YandV 9 and theV plug 37 to the point 54, VfromV thencethrough contact 55 of the key 31, ring contacts of the plug 37 and thejack r9, lower normal contact of the termittently, causing theintermittent lighting of the lamp 52.` The continuous lighting of thelamp 52 indica-tes to the testing operator that the relay 7 isimproperly adjusted to function in the intended manner when its Vcircuitis trayersedby maximum current and is slowly interrupted. The testtofunction properly under such conditions.

l Testing of alternating current relay.

VDesiring to test the alternating current supervisory .relay 6, theoperator actuatesthe key`32, whereupon the key 31 is restored to normalposition. Upon the actuation of this key 32, relays 40,-43, 41, v42 and47 are .relay 47 and the winding of the relay 51 to ing operator maythereupon adjust the relay' operatedL-'The circuit over which theserelays are operated may be traced from battery through the left-handwinding of relay 40, the windings of relays 43 and 41, sleeve contactsof the engaged plugs andjacks to the point 56 in the sleeve strandconnected with plug 37 and from thence through contact 57 of the key 32,tip contacts of the plug 37 and the jack 9 and the windings of relays 42and 47 to ground. It will be noted that the resistance 44 is notincluded in this circuit; therefore, marginal relays 43 and 47 attracttheir armatures, opening the normal and closing the alternate contacts.The operation of relay 43 disconnects the direct current supervisoryrelayA 7 from across the cord circuit A. The operation of the two relays42 and 47 associates with the relay 6 v the artificial line whichincludes the bridged resistance 21. With the keyf 32 depressed and therelays operated as described, the testing operator may now depress key34, whereupon relay 58 is operated over a circuit from battery throughthe left-hand winding of relay 40, windings of relays 43 and 41, sleevecontacts of the engaged plugs and jacks to the point 56, Vfrom thencethrough resistance 44, contact 59 of the key 32, contact 60 of the key34, resistance 61, ring contacts of the plug 37 and the jack 9, thelower alternate contact of relay 47 and the windings of relays 58 and 62to ground. Relay 62 is marginal and does not operate when resistances 44and 61 are included in circuit therewith.

The operation of relay 58 connects the source of alternating current 16in circuit with the relay 6 and the associated artificial line. Thiscircuit may be traced from the source of ringingcurrent 16 through thelamp 63, contact of relay 58, series resistances 18 and 17 of theartificial line, upper alternate contact of relay 47, upper contact ofrelay 42, tip contacts of the jack 10 and the plug 4, contact of relay41, upper normal contacts of splitting keys 64 and 65, winding of relay6, condenser 66, lower normal contacts of the splitting keys 65 and 64,ring contacts of the plug 4 and the jack 10, lower contact of relay 42,middle alternate contact of relay 47 and series resistances 19 and 20 ofthe artificial line to ground. If relay 6 is properly adjusted it willnot operate. However, ifv this relay 6 operates, the energizing circuitof the relay 24 will be opened and this relay 24 will release,establishing a circuit for the supervisory lamp 25 and the relay 26,which may be traced from battery through the contact of relay 40, thelamp 25 and the winding of relay 26 in parallel, contact of relay 24 andthe normal contact of listening key 67 to ground. Relay 26 in operatingestablishes a locking circuit for itself through its own contact,whereupon the lamp 25 remains lighted. Noting that the lamp 25 lights,the testing operator knows that the relay 6 is not properly adjusted.The key 34 may be allowed to assume its normal position to disconnectringing current from the relay 6 while this relay is being adjusted.After making the proper adjustments the key 34'is again depressed,whereupon the relay 6 does not respond to the ringing current and thelamp 25 is not lighted. It is to be understood, of course, that therelay 6 remains operated only so long as the key 34 is depressed. Whenthis relay is d'energized upon the release of the key 34, the circuit ofrelay 24 is again established. Before proceeding to test the relay 6under maximum ringing current conditions, listening 'key 67 ismomentarily actuated to open the locking circuit of relay 26, permittingits restoration to normal condition and the effacement of the lamp 25.The testing operator may then proceed to test relay 6. This is done byactuating the key 33, whereupon the key 32 is restored to normalposition. Upon the actuation of the key l 33, relays 40, 43, 41, 42 and47 operate over the previously traced circuit, the contact 68 of the key33, instead of the contact 57 of the key 32, being included therein. Thedepression of key 34 then causes the operation of relays 58 and 62 overa circuit from battery through the left-hand winding of relay 40, thewindings of the relays 43 and 41, sleeve` contacts of the engaged plugsand jack'sto the point 56, from thence through contact 69 of the key 33,contact 7 Oof the key 34, ring contacts of the plug 37 and the jack 9,lower alternate contact of relay 47, and the windings of relays 58 and62 to ground.

The operation of relay 58 connects the source of ringing current incircuit as before, while the operation of relay 62 removes the shortcircuit from about the resistance 22, thereby including this resistancein the bridge of the artificial line to alter the electrical conditionof the artificial line, thereby to provide maximum ringing current forrelay 6. lf relay 6 is properly adjusted relay 24 releases, whereuponrelay 26 locks up and maintains the lamp 25 lighted. If not properlyadjusted, the lamp 25 will not be lighted. The testing operator mayythereupon adjust the relay 6 until it responds properly to the maximumringing current.

What is claimed is:

1. In a testing system, a testing circuit, i'

sources of intermittent currents and alteriis nating current, a directcurrent and an alterj nating current relay connected with the testingcircuit, a circuit controlling device comprising a plurality of keysassociated with the testing circuit, a first relay responsive to theactuation of one of the keys to connect one of the sources ofintermittent current in circuit with the direct current relay, a secj,

ond relay responsive to the actuation of a Vso second one of the keysand cooperating with the first relay to connect another of the sourcesof intermittent current in circuit with the direct current relay, anartificial line, a third relay controlling 'the association of theartilicial line with the alternating current relay, and a fourth relayresponsive to the actuation of a third one of the keys to connect thesource of alternating current in circuit with the alternating currentYrelay and the artificial line.

2. In a testing system, ya testing circuit, sources of intermittentcurrents and alternating current, a direct current and an alternatingcurrent relay connected with thetesting circuit, avcircuit controllingdevice coinprising a plurality of keys associated with the testingcircuit, a first relay responsive to the actuation of one of the keysto` connect one of the sources of intermittent current in circuit withthe direct current relay, a second relay responsive to the actuation ofa second one of the keys and cooperating With the first relay to connectanother of the sources of intermittent current inV circuit With thedirect current relay, an artificial line, a third relay controlling` theassociation of the artificial line With the alternating current relay,a. fourth relay responsive to the actuation of a thirdone of the keys toconnect the source of alternating current in circuit with thealternating current relay and the artificial line, and a relayresponsive to the actuation of a fourth one of the keys When the thirdkey is actuated to alter the electrical characteristics of theartificial line.

3. In a testing system, a testing circuit, sources of intermittentcurrents and alternating current, a direct current and an alternatingcurrent relay connected With the testing circuit, a circuit controllingdevice comprising a plurality of keys associated With the testingcircuit, a first relay responsive to the actuation of one of the keys toconnect one of the sources of intermittent current in circuit With thedirect current relay, a second relay responsive to the actuation of asecond one of the keys and coperating With the first relay to connectanotherof the sources of intermittent current in circuit With the directcurrent relay, an artificial line, a third relay responsive to theactuation of a third one of the keys and cooperating with the firstrelay When energized to associate the artificial line with thealternating current relay, and a fourth relay energized upon theactuation of a fourth one of the keys While the first and third relaysare energized to connect the source of alternating current in circuitWith the alternating current relay and vthe artificial line.

4L. In a testing system, a testing circuit, sources of intermittentcurrents and alternating current, a direct current and an alternatingcurrent relay connected With the testing circuit, a circuit controllingdevice comprising a plurality of keys associated with the testingcircuit, a first relay responsive to the actuation of one of thekeys-.to connect one of the sources of interniittentrcurrent in circuitwith the direct current relay, a second relay responsive to theactuation of a second one of the keys and coperating With the firstrelay to connect another of the sources of intermittent current incircuit with the direct current relay, an artificial line, a third relayresponsive tothe actuationofa third one of the keys and cooperating Withthe first relay when energized to associate the artificial line with thealternating current relay, a fourth relay adapted When energized toconnect thesource of alternating current incircuit With thealternating-current relay and the artificial line, an energizing circuit.for the fourth relay established upon the actuation of a fourth one ofthe keys, and a marginal relay for the energizing circuit operating uponthe actuation of the fourth key-While a fifth one of the keys isactuated to alter the electrical characteristics of the artificial line.v i y 5. Infra testing' system, a testing circuit, sources ofintermittent currents and alternating current, direct current and analternating current relay connected With the testing circuit, a circuitcontrolling device coinprising a plurality of keys associated With thetesting circuit, a first relay' responsive to the actuation of one ofthe keys to connect one of the sources of intermittent current incircuit With the direct current relay, a second relay responsive to theactuation of a second one of the keys and'coperating with the firstrelay to connect another. of the'sources of intermittent current incircuit With the direct current relay, an artiv iicial line, a thirdrelay responsive to the actuation of a third one of the keys'andcooperating With thefirst relay when enervgized y to associate theartificial line with the alternating current relay, afourth relayvadapted When energized to connect the Source of alternating current incircuit with the alternating Vcurrent relay and the artificial line, andan energizing circuit for the foirth relay including a contact of thethird re ay.

6.'In a testing system, a testing circuit, a source of alternatingcurrent, an alternating current relay connected with the testingcircuit, a circuit controlling device comprising a plurality of keysassociated With the testing circuit, an artificial'line, a first relayadapted When energizedv upon` the actuation of one of the keys tocontrol the association of the Vartificial line With the alternatingcurrent relay, a second relay adapted When energized to connect thesource of alternating current in circuit With the alternating currentrelay and the artirelay, a second relay adapted When ener' gized toconnect the source of alternating current in circuit With thealternating cur-' rent relay and the artificial line, and an energizingcircuit Jfor the second relay including contacts of both actuated keys.

8. In a testing system, a testing circuit, a source of alternatingcurrent. an alternating current relay connected With the testingcircuit, a circuit controlling device cornnrising a pluralty of keysassociated With the testing circuit, an artificial line, a first relayaclanted when energized upon the actuation of one of the keys to controlthe association of the artificial line with the alternating currentrelay, a second relay adapted when energized to connect the source ofalternating current in circuit with the alternating current relay andthe artificial line. an energizing circuit for tbe second relayestablished unon the actuation of' a second one of the keys andincluding an engaged Contact of the energized first relay, and amarginal relay in the energizing cir cuit of the second relay operatingupon Copies of this patent may be obtained for the actuation of a thirdone of the keys to alter the electrical characteristics of theartificial line.

9. In a testing system, a testing circuit, a source of alternatingcurrent, an alternating current relay connected With the testingcircuit, a circuit controlling device comprising a plurality of keysassociated With the testing circuit, an artificial line, a first relayadapted when energized upon the actuation of one of the keys to controlthe association of the artificial line with the alternating currentrelay, a second relay adapted When energized to connect the source ofalternating current in circuit With the alternating current relay andthe artificial line. and an energizing circuit for tbe second relayjointly controlled by the first relay and a second one of the keys.

10. In a testing system, a testing circuit, a source of alternatingcurrent, an alternating current relay connected with the testingcircuit. a circuit controlling deyice cornprising a plurality of keysassociated with the testing circuit, an articial line. a first relayadapted when energized upon the actuation of one of the relays tocontrol the association of the artificial line with the alternatingcurrent relay, a second relay adapted when energized to connect thesource of alternating current in circuit with the alternating currentrelay and the artificial line, and an energizing circuit for the secondrelay controlled by the first relay and two of the keys.

In Witness whereof I hereunto subscribe my name this 21st day ofFebruary A. D.,

LOUIS A. MORTIMER.

ve cents each, by addressing the Commissioner of Patents,

Washington, D. C.

